Referring to FIG. 1, most toilet tanks include a float movable with the water level in the tank during flush cycles to operate a fill valve to refill the tank upon lowering of the water from a predetermined level and to close the fill valve once the tank is refilled to the predetermined level. During flush cycles, operation of a flush lever unseats a flush valve in the tank causing the water in the tank to be released through a discharge opening, and the float descends in response to lowering of the water level from the predetermined level, causing opening of the fill valve to refill the tank with closure of the flush valve. As the toilet tank is refilled, the float ascends in response to rising of the water level and, when the water level returns to the predetermined level, the float operates to close the fill valve and prevent further supply of water to the toilet tank.
A problem exists where the water level in the tank drops from the predetermined water level not due to flushing but due to leakage, typically through the flush valve, between flush cycles in that the float operates to open the fill valve allowing water to flow into the tank to replace that lost through leakage. During leakage, the float operates to keep the fill valve open such that water continually flows into the tank and through the discharge opening. On a small scale, this type of leakage is difficult to detect audibly and visually, such that the leakage problem can remain undetected and lead to wasted water. On a larger scale, the leakage can lead to flooding and property damage as well.
In many cases, consumers are alerted to major, continual leakage only through drastically high water utility bills while insidious or sporadic leakage can remain unrecognized with consumers inadvertently absorbing inflated water utility costs from the leakage. In addition to a direct economic burden on consumers, the aggregate effect of water leakage through deficient flush valves of toilet tanks is the waste of untold gallons of water, an increasingly scarce resource.
What is still desired is a new and improved mechanism for preventing leakage from a tank of a toilet. The mechanism will preferably prevent operation of a fill valve of the toilet unless and until a handle of the toilet is purposely operated to initiate a flush cycle.